JP2012088259A - On-vehicle radar device - Google Patents

On-vehicle radar device Download PDF

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JP2012088259A
JP2012088259A JP2010237029A JP2010237029A JP2012088259A JP 2012088259 A JP2012088259 A JP 2012088259A JP 2010237029 A JP2010237029 A JP 2010237029A JP 2010237029 A JP2010237029 A JP 2010237029A JP 2012088259 A JP2012088259 A JP 2012088259A
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JP5174880B2 (en
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Masa Mitsumoto
雅 三本
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Mitsubishi Electric Corp
三菱電機株式会社
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Abstract

PROBLEM TO BE SOLVED: To provide a radar device that does not make final output for vehicle control etc., unstable even if signal intensity of a target abruptly becomes small in a state similar to occurrence of multipath phasing and a result of a measurement stage becomes unstable.SOLUTION: An on-vehicle radar device includes a time-series correlation part 16 which generates an information set of the target including the position and relative speed of the target, a classification of the target, the number of times of time-series correlation establishment up to a current measurement period, a variation state of target information in a measurement before a current measurement, and the number of times of allowance of failure in establishment of time-series correlation while inputting information associated with the position and relative speed of the target by measurements taken by a measurement part 14 over plural periods and searching for a target which is correlative in time series; a storage part which stores the information sets of the target; and a result output part 17 which outputs only an information set which satisfies a preset condition among information sets of the target.

Description

  The present invention relates to an on-vehicle radar device, and more particularly to an on-vehicle radar device that detects a target object (hereinafter referred to as a target) and measures its position and relative speed, and can stabilize measurement result output. The present invention relates to a radar device.

  When the relative position of the target with respect to the in-vehicle radar satisfies a specific condition, the electromagnetic wave propagating between the radar and the target (direct wave) interferes with the electromagnetic wave propagating through the path from the radar to the road surface to the target (indirect wave), So-called multipath fading (hereinafter abbreviated as multipath) occurs, and the signal intensity related to the target becomes extremely small. For this reason, it is difficult to detect the target, and the detection result becomes unstable. Even if detected, the signal strength of the target is small and the so-called SNR (signal-to-noise ratio) is inadequate, resulting in an increase in error variation in measured values, resulting in positional variations and relative velocity variations from measurement to measurement. growing.

  As a prior art regarding the target in such a state, there is Patent Literature 1. In this prior art, a theoretical formula is calculated from the radar mounting height from the road surface, the target reflection point height from the road surface (where the reflection point is assumed to be one point-like reflection object), and the radar operating frequency. Thus, the distance range affected by the multipath is predicted. Also, while the target is passing through the distance range (elapsed time), the signal strength is low, so that even if the target is not detected, it is assumed that the target continues to exist and the target immediately before it is no longer detected. The vehicle is controlled smoothly by holding (holding) the distance and the relative speed or by continuing to output the linearly predicted result.

JP-A-6-34755

  However, in the prior art described in Patent Document 1 above, when the target is an actual vehicle or the like, a single target has a plurality of reflection points, or the height of the reflection point varies depending on the target. For this reason, there is a problem that it is not easy to estimate a multipath region by a theoretical formula.

Note that multipath does not occur only with the direct wave and the indirect wave described above, but can occur when there are two or more reflection points having substantially the same distance and relative velocity and different horizontal positions and heights. For example, a situation in which another vehicle overtakes a vehicle running in front of a radar-equipped vehicle (hereinafter referred to as the host vehicle) corresponds to this. Therefore, even if it is not determined to be a multipath area in the prior art, the target signal strength suddenly decreases for a certain period due to the same factors as multipath, and the target detection result suddenly becomes unstable in conjunction with this. , The variation of the measured value may increase. In the prior art, even when such a target is no longer detected, hold or linear prediction is performed only with the target information (distance and relative speed) immediately before that, so the error is caused by the acceleration / deceleration of the vehicle. There is a problem that when the target is in the detection state again, there is a difference in distance and relative speed, and a situation where the target is not regarded as the same target may occur.

  The present invention has been made to solve such problems, and even if the detection result or measurement accuracy suddenly becomes unstable at the measurement stage, the final output to vehicle control or the like is not destabilized. An object of the present invention is to obtain an in-vehicle radar device that makes it possible.

  The present invention is an on-vehicle radar device that is mounted on a vehicle and outputs information related to a target to be detected, and is a measurement that measures information related to the position and relative speed of a target in a predetermined time period. Information related to the position and relative velocity of each measurement by the measurement unit and the measurement unit over a plurality of periods, and searching for a target that is correlated in time series, at least information related to the target A result of outputting only a time series correlator that generates a target information set including one or more, a storage unit that stores the target information set, and a target information set that satisfies a preset condition Output unit, the target information set includes target position and relative velocity, target classification, and current measurement A time-series correlation satisfaction count up period, an in-vehicle radar device and a number of times to allow the variation state of the target information, the unsatisfied chronological correlation in this previous measurements.

  The present invention is an on-vehicle radar device that is mounted on a vehicle and outputs information related to a target to be detected, and is a measurement that measures information related to the position and relative speed of a target in a predetermined time period. Information related to the position and relative velocity of each measurement by the measurement unit and the measurement unit over a plurality of periods, and searching for a target that is correlated in time series, at least information related to the target A result of outputting only a time series correlator that generates a target information set including one or more, a storage unit that stores the target information set, and a target information set that satisfies a preset condition Output unit, the target information set includes target position and relative velocity, target classification, and current measurement This is an on-vehicle radar device that includes the number of time-series correlations established until the period, the fluctuation state of the target information in the measurement before this time, and the number of times that the time-series correlation is not established. Even if the measurement accuracy suddenly becomes unstable, the final output to the vehicle control or the like is not destabilized.

It is the block diagram which showed the structure of the vehicle-mounted radar apparatus concerning Embodiment 1 of this invention. It is a flowchart which shows the procedure of the production | generation and output of the target information set in the vehicle-mounted radar apparatus concerning Embodiment 1 of this invention.

Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described in detail. FIG. 1 is a block diagram showing a configuration of an in-vehicle radar device according to Embodiment 1 of the present invention.

In FIG. 1, 1 is a vehicle-mounted radar device, and 2 is a traveling speed sensor connected to the vehicle-mounted radar device.

  As shown in FIG. 1, the on-vehicle radar device 1 includes a control unit 11, a transmission / reception unit 12, a transmission / reception unit 13, a measurement unit 14, a storage unit 15, a time series correlation unit 16, and a result output unit. 17.

  Both the on-vehicle radar device 1 and the traveling speed sensor 2 are mounted on a vehicle. The traveling speed sensor 2 measures the traveling speed of the own vehicle. The on-vehicle radar device 1 radiates an electromagnetic wave, receives a reflected wave reflected by the target, and obtains a measurement result relating to the target based on the received signal and a traveling speed of the vehicle measured by the traveling speed sensor 2. Based on this, at least the position and relative speed of the target in the front-rear direction and the left-right direction are detected.

  Below, each component 11-17 which comprises the vehicle-mounted radar apparatus 1 is demonstrated.

The control unit 11 is configured by, for example, a dedicated logic circuit, a program in a general-purpose CPU (Central Processing Unit), or a combination of the two, and each of the constituent elements 12 to 17 of the in-vehicle radar device 1 described below. Control operation timing.

  In the transmission / reception unit 12 and the transmission / reception unit 13, the transmission signal generated by the transmission / reception unit 12 is radiated into the space as a transmission electromagnetic wave by the transmission / reception unit 13 under the control of the control unit 11. Further, under the control of the control unit 11, the transmission / reception unit 13 receives the reflected electromagnetic wave reflected by the target transmission or the like, and the transmission / reception unit 12 converts it into a reception signal.

  The measurement unit 14 receives a reception signal from the transmission / reception unit 12, measures information related to the target position and relative velocity at a preset constant time period, and outputs a measurement result. In the measurement unit 14, the input signal reception timing from the transmission / reception unit 12 and the output timing of the measurement result by the measurement unit 14 are controlled by the control unit 11. The measurement unit 14 includes a dedicated logic circuit, a general-purpose CPU, a program in a DSP (Digital Signal Processor), or a combination thereof. The measurement unit 14 performs measurement signal processing corresponding to the radar method and the angle measurement method used in the in-vehicle radar device 1 on the received signal, and measures at least the following four for the target.

・ Target number: Ktgt
-Polar coordinate system distance: Dst (i) {i = 1 to Ktgt}
・ Polar coordinate system radial relative speed: Vlc (i) {i = 1 ~ Ktgt}
-Polar coordinate system azimuth: Agl (i) {i = 1 to Ktgt}

  These measurement results are output from the measurement unit 14 to the storage unit 15 under the control of the control unit 11. The storage unit 15 stores these in a predetermined storage area under the control of the control unit 11.

  In addition, in order to measure the polar coordinate system distance Dst (i) and the polar coordinate system radial direction relative velocity Vlc (i), a known FMCW (Frequency Modulated Continuous Wave) method, a pulse Doppler method, and the like are realized. The transmission / reception unit 12 is configured so that transmission / reception is possible, and the transmission / reception timing is controlled by the control unit 11.

  Further, in order to measure the polar coordinate system azimuth angle Agl (i), the wave transmitting / receiving unit 13 has a mechanism for changing the direction of the transmitted / received electromagnetic wave in the polar coordinate system azimuth direction for a known monopulse angle measurement method, or a known array signal. A plurality of transmission elements and reception elements are provided for the processing angle measurement method, and the control unit 11 controls the direction of transmission / reception electromagnetic waves, the timing of transmission / reception of waves by the plurality of elements, and the like.

  The time series correlator 16 reads information related to the target position and relative velocity for each measurement obtained by the measuring unit 14 from the storage unit 15 over a plurality of periods, and searches for a target having a time series correlation. However, the target position and relative velocity, the target classification, j the number of time series correlations established up to the current measurement period, the fluctuation state of the target information in the measurement before this time, and the number of times that the time series correlation is not established Generate an information set for the target containing The target information set is stored in the storage unit 15 under the control of the control unit 11.

  Here, the target information set used below will be described. The target information set includes the previous measurement: S0 and the current measurement: S1, and at least the following information as the same type of information, the number of targets (previous measurement: KtgtS0, current measurement: KtgtS1) I have a minute.

-Orthogonal coordinate system longitudinal position: S0_Ry (i), S1_Ry (j)
-Cartesian coordinate system horizontal position: S0_Rx (i), S1_Rx (j)
・ Correct coordinate system longitudinal speed: S0_Rv (i), S1_Rv (j)
-Number of time-series correlations established: S0_Ns (i), S1_Ns (j)
-Target classification by speed: S0_Cv (i), S1_Cv (j)
-Orthogonal coordinate system longitudinal position fluctuation state: S0_Fy (i), S1_Fy (j)
-Cartesian coordinate system horizontal position fluctuation state: S0_Fx (i), S1_Fx (j)
・ Cartesian coordinate system longitudinal relative velocity fluctuation state: S0_Fv (i), S1_Fv (j)
-Allowable number of time series correlation failure: S0_Np (i), S1_Np (j)

  However, i = 1 to KtgtS0 and j = 1 to KtgtS1.

  The result output unit 17 outputs only the target information set generated by the time-series correlation unit 16 that satisfies a preset condition. An example of the condition will be described later.

  Hereinafter, the generation and output procedure of the target information set S1 in this measurement will be described in detail using the flowchart of FIG. 2 as the operations of the storage unit 15, the time series correlation unit 16, the result output unit 17, and the traveling speed sensor 2. State.

  Note that the control unit 11 controls the storage unit 15 and the time-series correlation unit 16 after the measurement unit 14 finishes outputting the target information set S0 in the previous measurement to the storage unit 15 under the control of the control unit 11. The result output unit 17 and the traveling speed sensor 2 are controlled to generate and output the target information set S1 in the current measurement.

  Among these, the memory | storage part 15 is comprised from memory | storage devices, such as memory (RAM) and a hard disk, and the time series correlation part 16 and the result output part 17 are a dedicated logic circuit, general purpose CPU, the program in DSP, or Consists of these combinations.

  In the flowchart of FIG. 2, first, in step S201, the time-series correlation unit 16 initializes the target number KtgtS1 for current measurement (KtgtS1 = 0). At this time, the value of KtgtS0 is recorded in the storage unit 15 as the previous result. However, KtgtS0 = 0 is set immediately after the radar apparatus is activated and before the measurement is performed.

  Next, in step S202, the time-series correlation unit 16 reads the target number KtgtS0 for the previous measurement from the storage unit 15, determines whether KtgtS0 = 0, and if KtgtS0 = 0, proceeds to step S203, and KtgtS0 If ≠ 0, the process proceeds to step S204.

  In step S203, the time-series correlation unit 16 reads the target number Ktgt measured this time by the measurement unit 14 from the storage unit 15, and repeats the processes of steps S203a to S203b as many times as the target number Ktgt.

  Hereinafter, in the description of steps S203a to S203b, i = 1 to Ktgt, and the current measurement result of the i-th target: {Dst (i), Vlc (i), Agl (i)} is processed.

  In step S203a, the time series correlation unit 16 generates each piece of information S1 and stores it in the storage unit 15 as described below.

  First, from the polar coordinate system distance Dst (i) and the polar coordinate system azimuth angle Agl (i) read from the storage unit 15, the orthogonal coordinate system front-rear direction position S1_Ry (KtgtS1) and the orthogonal coordinate system left-right direction position S1_Rx (KtgtS1) are calculated. And stored in the storage unit 15.

  For example, for the polar coordinate system azimuth angle Agl (i), if the front of the vehicle is 0 [deg], the left side of the traveling direction is defined as the minus region and the right side is defined as the plus region, the Cartesian coordinate system longitudinal direction position S1_Ry (KtgtS1) And Cartesian coordinate system left-right direction position S1_Rx (KtgtS1) is calculated by the following equation.

S1_Ry (KtgtS1) [m] = Dst (i) [m] × cos {Agl (i) [deg]}
S1_Rx (KtgtS1) [m] = Dst (i) [m] × sin {Agl (i) [deg]}

  Next, the orthogonal coordinate system longitudinal relative speed S1_Rv (KtgtS1) is calculated from the polar coordinate system radial relative speed Vlc (i) and the polar coordinate system azimuth angle Agl (i) read from the storage unit 15, and the storage unit 15 To remember.

  For example, for polar coordinate system azimuth angle Agl (i), the front of the vehicle = 0 [deg], the left side in the direction of travel is defined as the minus region, the right side is defined as the plus region, and the polar coordinate system radial direction relative velocity Vlc (i) and Cartesian coordinates For the system longitudinal direction relative speed S1_Rv (KtgtS1), when the approach time is defined as minus, the orthogonal coordinate system longitudinal direction relative speed S1_Rv (KtgtS1) is calculated by the following equation.

  S1_Rv (KtgtS1) [m / s] = Vlc (i) [m / s] ÷ cos {Agl (i) [deg]}

  Next, the number of time series correlation establishment S1_Ns (KtgtS1) is initialized (S1_Ns (KtgtS1) = 0) and stored in the storage unit 15.

  Next, the sum of the Cartesian coordinate system longitudinal relative speed S1_Rv (KtgtS1) and the input Vsbj1 output of the vehicle's running speed sensor 2 is compared with a preset speed value: Vmov, and the target is classified by speed. S1_Cv (KtgtS1) is determined and stored in the storage unit 15.

For example, for the Cartesian coordinate system longitudinal relative speed S1_Rv (KtgtS1), the approach time is defined as minus,
| S1_Rv (KtgtS1) + Vsbj1 | ≧ Vmov
In the case of, the target classification by speed S1_Cv (KtgtS1) is set as a target moving relative to the ground (moving target),
| S1_Rv (KtgtS1) + Vsbj1 | <Vmov
In this case, the target classification S1_Cv (KtgtS1) based on the speed is set as a target that is stopped with respect to the ground (stop target).

Next, the orthogonal coordinate system front-rear direction position fluctuation state S1_Fy (KtgtS1) is initialized (S1_Fy (KtgtS1) = 0) and stored in the storage unit 15.
Also, the horizontal coordinate position variation state S1_Fx (KtgtS1) in the orthogonal coordinate system is initialized (S1_Fx (KtgtS1) = 0) and stored in the storage unit 15.
The orthogonal coordinate system longitudinal direction relative speed fluctuation state S1_Fv (KtgtS1) is initialized (S1_Fv (KtgtS1) = 0) and stored in the storage unit 15.
Further, the allowable time series correlation failure count S1_Np (KtgtS1) is initialized (S1_Np (KtgtS1) = Ndef) and stored in the storage unit 15.
Here, Ndef is a preset number of times.

  In step S203b, the time-series correlation unit 16 increments the target number KtgtS1 in the current measurement (KtgtS1 = KtgtS1 + 1). If KtgtS1> Ktgt as a result of the increment, the process of step S203 is terminated, and the process proceeds to step S206.

  On the other hand, in step S204, the time-series correlation unit 16 repeats steps S204a to S204i as many times as the number of times KtgtS0 read from the storage unit 15. Hereinafter, in the description of step S204a to step S204i, i = 1 to KtgtS0, and the i-th previous measurement information set: S0 is processed.

  In step S204a, the time-series correlator 16 sets a temporary minimum value for selection: Tmp used in the determination in step S204b4 described later to a sufficiently large value (a value sufficiently larger than the result calculated in step S204b3): Emax. (Tmp = Emax) and an invalid value is set to the information set candidate number Cnd (Cnd = 0).

  In step S204b, the time-series correlation unit 16 reads the target number Ktgt measured this time by the measurement unit 14 from the storage unit 15, and repeats steps S204b1 to S204b6 by the number of times corresponding to Ktgt.

  Hereinafter, in the description from step S204b1 to step S204b6, j = 1 to Ktgt, and the jth current measurement result: {Dst (j), Vlc (j), Agl (j)} is processed.

  In step S204b1, the time-series correlation unit 16 performs the following three predicted values {SpRy (i), SpRx from the information set of the previous observation: S0 by linear prediction based on a predetermined measurement cycle (time interval) set in advance. (i), SpRv (i)} is calculated.

  First, prediction is performed from the orthogonal coordinate system longitudinal direction position S0_Ry (i) and the orthogonal coordinate system longitudinal direction relative velocity S0_Rv (i) of the previous measurement read from the storage unit 15, and the orthogonal coordinate system longitudinal direction predicted position in the current measurement is SpRy. (i) is calculated. For example, when the approach time is defined as minus with respect to the orthogonal coordinate system longitudinal direction relative speed S0_Rv (i), it is calculated by the following equation.

  SpRy (i) [m] = S0_Ry (i) [m] + S0_Rv (i) [m / s] x measurement period [s]

  Next, prediction is performed from the orthogonal coordinate system horizontal direction position S0_Rx (i) of the previous measurement read from the storage unit 15, and the orthogonal coordinate system horizontal direction predicted position: SpRx (i) in the current measurement is calculated. For example, it calculates with the following formula.

  SpRx (i) [m] = S0_Rx (i) [m]

  Next, prediction is performed from the orthogonal coordinate system longitudinal relative velocity S0_Rv (i) of the previous measurement read from the storage unit 15, and the orthogonal coordinate system longitudinal predicted relative velocity: SpRv (i) in the current measurement is calculated. For example, when the approach time is defined as minus with respect to the orthogonal coordinate system longitudinal direction relative speed S0_Rv (i), it is calculated by the following equation.

  SpRv (i) [m / s] = S0_Rv (i) [m / s]

  Further, the following three values {Ry (j), Rx (j), Rv (j)} are calculated. From the polar coordinate system distance Dst (j) and the polar coordinate system azimuth angle Agl (j) read from the storage unit 15, a provisional orthogonal coordinate system longitudinal position: Ry (j) and a provisional orthogonal coordinate system left-right position: Rx ( j) is calculated. For example, the polar coordinate system azimuth angle Agl (j) is calculated by the following formula when the front of the vehicle is 0 [deg], the left side in the traveling direction is defined as a minus region, and the right side is defined as a plus region.

Ry (j) [m] = Dst (j) [m] × cos {Agl (j) [deg]}
Rx (j) [m] = Dst (j) [m] × sin {Agl (j) [deg]}

  Next, a provisional orthogonal coordinate system longitudinal relative velocity: Rv (j) is calculated from the polar coordinate system radial relative velocity Vlc (j) and the polar coordinate system azimuth angle Agl (j) read from the storage unit 15. For example, for the polar coordinate system azimuth angle Agl (j), the front of the vehicle = 0 [deg], the left side of the traveling direction is defined as a minus region, the right side is defined as a plus region, and the polar coordinate system radial relative speed Vlc (j) and orthogonal coordinates For the system longitudinal direction relative speed Rv (j), when the approach time is defined as minus, it is calculated by the following equation.

  Rv (j) [m / s] = Vlc (j) [m / s] ÷ cos {Agl (j) [deg]}

  Next, with respect to these obtained values, the magnitude of the difference is calculated by the following combination.

δy = | SpRy (i) −Ry (j) |
δx = | SpRx (i) −Rx (j) |
δv = | SpRv (i) −Rv (j) |

  In step S204b2, the time series correlator 16 determines whether all of the following conditions are satisfied with respect to the magnitudes δy, δx, and δv calculated in step S204b1, and if satisfied, proceeds to step S204b3. Otherwise, the process proceeds to step S204b6.

δy <εy
δx <εx
δv <εv

  Here, εy, εx, and εv are preset allowable error values.

  In step S204b3, the time series correlation unit 16 calculates the evaluation value for selection: Est from the magnitude of the difference, for example, as the sum of squares of the differences.

  Est = (δy × δy) + (δx × δx) + (δv × δv)

  In step S204b4, the time series correlation unit 16 compares the evaluation value Est for selection with the provisional minimum value Tmp for selection. As a result, if Est <Tmp, the process proceeds to step S204b5. On the other hand, if Est ≧ Tmp, the process proceeds to step S204b6.

  In step S204b5, the time series correlator 16 replaces the value of Tmp with the evaluation value Est for selection (Tmp = Est), and adds the information set candidate number Cnd to the number of the current measurement result being processed: j (j (Th target) is set (Cnd = j).

  Step S204b6 is a step only as a destination for conditional branching, and does nothing.

  In this way, the processing from step S204b1 to step S204b6 is repeated for the number of times of Ktgt. When the number of times of Ktgt is completed, the process proceeds to step S204c.

  In step S204c, the time series correlator 16 determines whether or not the information set candidate number Cnd is an invalid value. If it is not an invalid value (Cnd ≠ 0), the process proceeds to step S204d. On the other hand, if the information set candidate number Cnd is an invalid value (if Cnd = 0), the process proceeds to step S204f.

  In step S204d, the time-series correlation unit 16 assumes that linear prediction has been established between the information set S0 of the i-th previous measurement being processed and the Cnd (= j) -th current measurement result, and the i-th S0 Based on the Cnd (= j) -th information of the current measurement result and the travel speed sensor 2 output Vsbj1 of the host vehicle, the following processing is performed to calculate and set the information of the KtgtS1st S1. 15 stores.

  From the result calculated in step S204b1, Ry (Cnd = j), Ry (Cnd = j), Ry (Cnd = j), SpRy (i), SpRx (i), SpRv (i) The direction position S1_Ry (KtgtS1), the Cartesian coordinate system left-right direction position S1_Rx (KtgtS1), and the Cartesian coordinate system longitudinal relative speed S1_Rv (KtgtS1) are calculated and stored in the storage unit 15. For example, it calculates with the following formula | equation.

S1_Ry (KtgtS1) = (1−α) × Ry (Cnd) + α × SpRy (i)
S1_Rx (KtgtS1) = (1−β) × Rx (Cnd) + β × SpRx (i)
S1_Rv (KtgtS1) = (1−γ) × Rv (Cnd) + γ × SpRv (i)

  However, α, β, and γ are constants of 0 or more and less than 1.

  An arbitrary value is added to S0_Ns (i) to obtain a new time-series correlation establishment count S1_Ns (KtgtS1), which is stored in the storage unit 15. For example, as the following expression, 1 is added as the above arbitrary value.

  S1_Ns (KtgtS1) = S0_Ns (i) +1

  Further, the differences δy, δx, and δv calculated in step S204b1 are added to the fluctuation state of the previous measurement, recorded in the following information, and stored in the storage unit 15.

S1_Fy (KtgtS1) ← {S0_Fy (i) and δy}
S1_Fx (KtgtS1) ← {S0_Fx (i) and δx}
S1_Fv (KtgtS1) ← {S0_Fv (i) and δv}

  However, each variation state stores only the latest measurement result L times, and stores only the finite number of results without storing the previous state. For example, each variation state is prepared as an L-dimensional information storage array, and δy, δx, and δv are stored in a so-called cycle.

  The time series correlator 16 includes the Cartesian coordinate system longitudinal relative speed S1_Rv (KtgtS1) and the vehicle speed sensor 2 output Vsbj1, or S1_Rv (KtgtS1) and Vsbj1, and the Cartesian coordinate system longitudinal relative speed S0_Rv (i). To classify the targets based on the speed relative to the ground. That is, it is classified as moving to the ground (moving target) or stopped against the ground (stop target), and the classification result is set to the target classification S1_Cv (KtgtS1) by speed And stored in the storage unit 15. For example, only when both of the following two conditions are satisfied, the target is stopped with respect to the ground (stop target).

| S1_Rv (KtgtS1) + Vsbj1 | <Vmov
| S0_Rv (i) + Vsbj1 | <Vmov

  Other than that, it is assumed that the target is moving relative to the ground (moving target).

  Further, based on each fluctuation state, the allowable time series correlation failure count S1_Np (KtgtS1) is set and stored in the storage unit 15. For example, if the target is classified as a target moving relative to the ground from the target classification S1_Cv (KtgtS1) based on speed, and is determined to be in the same lane as the own vehicle from the Cartesian coordinate system left and right position S1_Rx (KtgtS1), it is orthogonal While recording the L-axis position fluctuation state S1_Fy (KtgtS1) in the coordinate system for L times, the difference δy in Ny {q} times is less than the preset front-rear position fluctuation difference: Wy [m], and S1_Fx During the recording of L times of (KtgtS1), if the magnitude of the difference δx is less than the preset horizontal position variation difference: Wx [m] in Nx {q} times, the following is assumed.

  Allowable number of time series correlation failure S1_Np (KtgtS1) = preset number of times: Nyx {q}

  In other words, if the position of the target moving forward and backward with respect to the ground is small, the target moves almost the same as the vehicle, and the target does not suddenly disappear. To do.

At this time, regarding Ny {q}, Nx {q}, and Nyx {q}, a plurality of combinations may be prepared with q> 1. For example,
From S1_Cv (KtgtS1), it is classified as a target that is stopped against the ground,
From S1_Rx (KtgtS1), if it is determined that it is in the same lane as the vehicle,
During recording L times of S1_Fx (KtgtS1), the difference δx in Nx {q} times is less than the preset lateral position difference: Wx [m], and
During recording L times of S1_Fv (KtgtS1), if the magnitude of the difference δv is less than the preset forward / backward relative speed fluctuation difference Nv {q} times: Wv [m / s]
S1_Np (KtgtS1) = preset number of times: Nxv {q}
And

  That is, if the fluctuation of the left-right position and relative speed of the target that is stopped against the ground in front is small, the vehicle is approaching the target and the target will not suddenly disappear. To do.

  At this time, regarding Nx {q}, Nv {q}, and Nxv {q}, a plurality of combinations may be prepared with q> 1.

When setting S1_Np (KtgtS1), if S1_Np (KtgtS1) <S0_Np (i),
S1_Np (KtgtS1) = S0_Np (i)
As
If time-series correlation is established over a plurality of measurement periods, the largest value among the allowable times of time-series correlation obtained before this time may be adopted.

  Further, instead of directly setting S1_Np (KtgtS1) by the number of times, it may be set as a once-permitted orthogonal coordinate system longitudinal position interval: Ryy, and the number of times may be set by the relative speed at that time as shown in the following equation.

  S1_Np (KtgtS1) = {Ryy [m] ÷ S1_Rv (KtgtS1) [m / s]} ÷ Measurement period [s]

  In step S204e, the time-series correlation unit 16 increments KtgtS1 (KtgtS1 = KtgtS1 + 1). If KtgtS1> KtgtS0 as a result of the increment, the process of step S204 is terminated and the process proceeds to step S205.

  On the other hand, in step S204f, the time series correlator 16 reduces the value from S0_Np (i) by an arbitrary value, and sets it as the provisional allowable time series correlation failure count: Np. For example, 1 is subtracted as in the following equation.

  Np = S0_Np (i) −1

  In step S204g, the time-series correlation unit 16 compares Np obtained in step S204f with a preset number of times: Nb. If Np (KtgtS1)> Nb as a result of the comparison, the process proceeds to step S204h. On the other hand, if Np (KtgtS1) ≦ Nb, the process proceeds to step S204i.

  In step S204h, the time-series correlation unit 16 does not establish a time-series correlation in the current measurement result for the information set S0 of the i-th previous measurement being processed. Based on Vsbj1 and Vsbj0, information of KtgtS1st S1 is calculated, set, and stored in the storage unit 15.

First, Np obtained in step S204f is set as S1_Np (KtgtS1) (S1_Np (KtgtS1) = Np),
Store in the storage unit 15.

  For other information, for example, the following processing is performed.

  S1_Ry (KtgtS1) and S1_Rv (KtgtS1) are calculated from the information of S1_Cv (KtgtS1) = S0_Cv (i) by a different method depending on the target classification and stored in the storage unit 15.

  In the case of a target moving with respect to the ground, the difference between Vsbj1 and Vsbj0 in the previous measurement read from the storage unit 15 is compared with a preset vehicle speed fluctuation value: Vdff, and | Vsbj1−Vsbj0 | <Vdff If so, the linear prediction result obtained in step S204b1 is used as it is as follows.

S1_Ry (KtgtS1) = SpRy (i)
S1_Rv (KtgtS1) = SpRv (i)

  On the other hand, if | Vsbj1−Vsbj0 | ≧ Vdff, the following formula is used.

S1_Rv (KtgtS1) = SpRv (i) − {Vsbj1−Vsbj0}
S1_Ry (KtgtS1) = S0_Ry (i) + S1_Rv (KtgtS1) × Measurement period [s]

  In addition, if the target is stationary with respect to the ground, S1_Rv (KtgtS1) is calculated using Vsbj1 and the linear prediction result obtained in step 204b1 (S204b1). Make it correspond. For example, the following equation is used.

S1_Rv (KtgtS1) = {SpRv (i) + Vsbj1} / 2
S1_Ry (KtgtS1) = S0_Ry (i) + S1_Rv (KtgtS1) × Measurement period [s]

  For the remaining S1_Rx (KtgtS1), S1_Ns (KtgtS1), S1_Cv (KtgtS1), S1_Fy (KtgtS1), S1_Fx (KtgtS1), S1_Fv (KtgtS1), for example, the information of S0 is stored as it is, and stored in the storage unit 15.

S1_Rx (KtgtS1) = S0_Rx (i)
S1_Ns (KtgtS1) = S0_Ns (i)
S1_Cv (KtgtS1) = S0_Cv (i)
S1_Fy (KtgtS1) = S0_Fy (i)
S1_Fx (KtgtS1) = S0_Fx (i)
S1_Fv (KtgtS1) = S0_Fv (i)

  In step S204i, the time-series correlator 16 does not leave the information set for the next time and thereafter, assuming that no target actually exists for the information set S0 of the i-th previous measurement being processed.

  In step S205, the time series correlation unit 16 stores KtgtS1 in the storage unit 15.

  In step S206, the result output unit 17 repeats steps S206a to S206c as many times as KtgtS1 read from the storage unit 15. Hereinafter, in the description of steps S206a) to S206c), i = 1 to KtgtS1, and the i-th current measurement information set: S1 is handled.

  In step S206a, the result output unit 17 reads S1 from the storage unit 15, and proceeds to step S206b if a preset condition is satisfied. On the other hand, if not satisfied, the process proceeds to step S206c. For example, the following conditions are used.

  S1_Ns (i)> {Number of times set in advance: Nout}

  In step S206b, the result output unit 17 outputs information determined in advance as information necessary for vehicle control out of S1 being processed by the control of the control unit 11. For example, S1_Ry (i), S1_Rx (i), and S1_Rv (i) are output. This output is input to, for example, another device (not shown) for vehicle control and used for vehicle control.

  Step S206c is a step only as a conditional branch destination and does nothing.

  In step S207, after the output by the result output unit 17 is finished, the control unit 11 temporarily stores the information of KtgtS0 and S0 stored in the storage unit 15 in order to make S1 the information set of the previous measurement in the next measurement. Clear (reinitialize), store the value of KtgtS1 in KtgtS0, copy the information of S1 to the storage area of S0, and then clear (reinitialize) the information of S1.

  In step S208, the time-series correlation unit 16 performs the following processing to set Vsbj1 to Vsbj0 in the next measurement, and stores Vsbj0 and Vsbj1 in the storage unit 15 under the control of the control unit 11.

Vsbj0 = Vsbj1
Vsbj1 ← clear (reinitialization)

  As described above, the on-vehicle radar device according to the present embodiment includes the measurement unit 14 that measures information on the target position and the relative speed at a constant time period, and the traveling speed that measures the traveling speed of the radar-equipped vehicle. Input information related to the sensor 2 and the target position and relative velocity for each measurement over a plurality of periods, and search for a target that is correlated in time series, and the target position and relative velocity and target classification A time-series correlation unit that generates a target information set including the number of time-series correlations established until the current measurement cycle, the fluctuation state of the target information in the measurement before this time, and the number of times that the time-series correlation is not allowed to be established 16, a storage unit 15 for storing the target information set, and only those satisfying the preset conditions for the target information set. And a result output unit 17. With this configuration, the in-vehicle radar device according to the present embodiment is not detected at the measurement stage if the information set obtained by the time-series correlation over the plurality of measurement cycles before this time satisfies a preset condition. The target can be output in the final result for vehicle control. Therefore, the on-vehicle radar device according to the present embodiment has an effect that the final output to vehicle control or the like is not destabilized even if the detection result or measurement accuracy suddenly becomes unstable at the measurement stage. The vehicle can be controlled smoothly. As a result, not only when multipath fading occurs, for example, another vehicle overtakes the vehicle traveling in front of the host vehicle, causing the same target as multipath fading. Even if the signal intensity suddenly decreases for a certain period and the target detection result suddenly becomes unstable in conjunction with this, the target measurement result output can be stabilized.

  Further, in the on-vehicle radar device according to the present embodiment, when the time series correlator 16 no longer detects the target in the current measurement cycle, the time series correlation of the target information set in the measurement cycle immediately before it is no longer detected. If the number of times that the failure is allowed is larger than a preset number of times, it is assumed that the target exists, and the target position and relative speed of the target information set in the measurement cycle immediately before detection is stopped, and the traveling speed of the radar-equipped vehicle Based on this, the target position and relative speed in the current measurement cycle were calculated. As a result, for the target that is not detected in the measurement stage, the position and relative speed that are output as the final result can be calculated based on the position immediately before the non-detection, the relative speed, and the own vehicle speed.

  Further, in the on-vehicle radar device according to the present embodiment, the storage unit 15 has the fluctuation state of the target information in the measurement before this time as the fluctuation state of the front-rear direction position, the fluctuation state of the left-right direction position, and the relative speed of the front-rear direction. The fluctuation state was recorded for multiple measurement cycles before this time. Thereby, as the variation state of the target information included in the information set, the variation state of the front-rear direction position, the left-right direction position, and the relative speed can be recorded for a plurality of measurement periods.

  Further, in the on-vehicle radar device according to the present embodiment, the time series correlation unit 16 sets the number of times that the time series correlation is not allowed based on the fluctuation state of the target information in the previous measurement. . Thereby, based on the variation result of the target information included in the information set, it is possible to set, for each target, the length of the period during which output is not detected in the measurement stage but continues to be output in the final result.

  In the on-vehicle radar device according to the present embodiment, the time-series correlation unit 16 provides a moving target and a stop target based on the speed with respect to the ground as the target classification included in the target information set. The method of setting the number of times to allow time series correlation failure is different depending on the classification. Thereby, the setting method of the length of the period during which the output is not detected in the measurement stage but continues to be output in the final result can be changed depending on the classification of the target included in the information set.

  Further, in the on-vehicle radar device according to the present embodiment, the time series correlation unit 16 does not establish the maximum time series correlation in the previous measurement period during the measurement period in which the time series correlation is continuously established. Is allowed to be the number of times that the time series correlation is not established in the current measurement cycle. As a result, when time-series correlation is established in consecutive measurement cycles, the length of the period that is not detected in the measurement stage but continues to be output in the final result is set to the maximum value obtained continuously before this time. be able to.

  Further, in the on-vehicle radar device according to the present embodiment, when the time-series correlation unit 16 sets the number of times that the time-series correlation is not allowed, it is initially set as the interval between the front and rear direction positions. The number of times is calculated based on the relative speed of the target and the measurement cycle. This makes it possible to calculate the number of times that the time-series correlation is not allowed based on the length of the period during which detection is not performed in the measurement stage but the output is continued in the final result, the position interval, the target relative speed, and the observation period.

  DESCRIPTION OF SYMBOLS 1 In-vehicle radar apparatus, 2 Travel speed sensor, 11 Control part, 12 Transmission / reception part, 13 Transmission / reception part, 14 Measurement part, 15 Storage part, 16 Time series correlation part, 17 Result output part

Claims (7)

  1. An on-vehicle radar device that is mounted on a vehicle and outputs information about a target to be detected,
    A measurement unit that measures the target number, polar coordinate system distance, polar coordinate system radial direction relative speed, polar coordinate system azimuth angle as target information at a predetermined fixed time period;
    While inputting the traveling speed of the own vehicle detected by the traveling speed sensor provided in the vehicle, the target information for each measurement by the measuring unit is input over a plurality of periods, and the target has a correlation in time series. While searching, the target position and relative speed, target classification, the number of time series correlations established up to the current measurement period, the fluctuation state of the target information in the measurement before this time, and the time series correlation failure are allowed. A time series correlator for generating a target information set including the number of times,
    A storage unit for storing the information set of the target;
    An in-vehicle radar device comprising: a result output unit that outputs only a target information set stored in the storage unit that satisfies a preset condition.
  2. If the target is not detected in the current measurement cycle, the time-series correlation unit may allow the number of times that the time-series correlation of the target information set in the measurement cycle immediately before it is no longer detected to be greater than a preset number of times. Based on the target position and relative speed in the target information set in the measurement period immediately before the target is no longer detected and the traveling speed of the vehicle, the target position and relative speed in the current measurement period are The on-vehicle radar device according to claim 1, wherein the on-vehicle radar device is calculated.
  3. The storage unit, as the fluctuation state of the target information in the measurement before this time, the fluctuation state of the front-rear direction position, the fluctuation state of the left-right direction position, the fluctuation state of the front-rear direction relative speed, for a predetermined plurality of measurement periods before this time, The on-vehicle radar device according to claim 1, wherein recording is performed.
  4. The said time series correlation part sets the frequency | count to which failure of time series correlation is permitted based on the fluctuation | variation state of the target information in the measurement before this time. The Claim 1 thru | or 3 characterized by the above-mentioned. In-vehicle radar system.
  5. The time series correlator sets a moving target and a stop target classified based on whether the target is included in the target information set according to whether the target moves or stops, and sets the time series according to the classification of these targets. The in-vehicle radar device according to any one of claims 1 to 4, wherein a method of setting a number of times that the correlation failure is allowed is different.
  6. The time-series correlation unit determines the number of times that the maximum time-series correlation in the previous measurement period is allowed during the measurement period in which the time-series correlation is continuously established, and the time-series correlation in the current measurement period. The on-vehicle radar device according to any one of claims 1 to 5, characterized in that the number of times that the failure is not allowed is set.
  7. When setting the number of times that the time-series correlation is not allowed, the time-series correlation unit first sets the interval in the front-rear direction position, and the number of times based on the interval, the relative speed of the target, and the measurement cycle The on-vehicle radar device according to any one of claims 1 to 6, wherein the on-vehicle radar device is calculated.
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JP2009181315A (en) * 2008-01-30 2009-08-13 Toyota Motor Corp Object detection device

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JP2003240843A (en) * 2002-02-19 2003-08-27 Denso Corp Fmcw radar unit and program
JP2004226120A (en) * 2003-01-20 2004-08-12 Denso Corp Radar device and program
JP2008051614A (en) * 2006-08-24 2008-03-06 Honda Motor Co Ltd Object detection device
JP2008051615A (en) * 2006-08-24 2008-03-06 Honda Motor Co Ltd Object detection device
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